Check out the blackboard. That box on the left has all of the information you need to know about one element. It tells you the mass of one atom, how many pieces are inside, and where it should be placed on the periodic table.

In the next section we're going to cover electron orbitals or electron shells. This may be a new topic to some of you.

Electrons In The Shells

Take a look at the picture below. Each of those colored balls is an electron. In an atom, the electrons spin around the center, also called the nucleus. The electrons like to be in separate shells/orbitals. Shell number one can only hold 2 electrons, shell two can hold 8, and for the first eighteen elements shell three can hold a maximum of eight electrons. As you learn about elements with more than eighteen electrons you will find that shell three can hold more than eight. Once one shell is full, the next electron that is added has to move to the next shell.

So... for the element of PHOSPHORUS, you already know that the atomic number tells you the number of electrons. That means there are 15 electrons in a Phosphorus atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and five in shell three.

Examples of Compounds with Phosphorus

Phosphine

This is PH3, also known as phosphine. Phosphine is a gas and is made up of three hydrogen (H) atoms and one phosphorus (P) atom. The hydrogen atoms share each of their electrons to fill the outer shell of the phosphorus atom. Also the hydrogens get to use an electron to fill their shells.

Aluminum Phosphide

Aluminum (Al) and phosphorus (P) can also bond. Aluminum happens to have three extra electrons. Luckily, every phosphorus atom is looking to gain three electrons. It's a perfect match! Something to notice though, look how they have a bond with six electrons. That bond is known as a triple bond. When a bond has two electrons it is a single bond. When a bond has four electrons it is a double bond. Well take a look at the dots and see what a triple bond looks like!